Hydraulic elevator.



J. S. HOYT.

HYDRAULIC ELEVATOR.

APPLICATION FILED FEB. 2. 1907 Patented Ap1220, 1915.

wit names THE NORRIS PETERS c0, PHOTO-LITHD.. WASHINGTON, D.

FFI@E.

JOHN SHERMAN HOYT, OF DARIEN, CONNECTICUT.

HYDRAULIC ELEVATOR.

Application filed February 2, 1907.

T all whom it may concern Be it known that I, Join: S. HOYT, a citizen of the United States, residing at Darien, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Hydraulic Elevators, of which the following is a full, clear, and exact specification.

This invention relates to hydraulic elevators, and has particular reference to improvements whereby the unbalanced dead load in plunger elevators may be eliminated, and enabling the power to be used entirely in moving the live load, without increasing the difficulty of controlling the car when in motion.

In plunger elevators, the size of the counterweight is usually fixed, and it is customary to underbalance the car to an appreciable degree in order to enable it to be controlled. By reason of the large masses of plunger and counterweight in motions and the dead load, there is difficulty in starting and stopping the car as quickly as is desirable without bounding or straining the plunger and also there is a waste of power in moving this unbalanced, or dead load.

The object of this invention is to provide, in a plunger elevator system, means whereby the car can be closely counterbalanced, in combination with means whereby the effect of the counterbalance may be varied automatically in starting and stopping the car, according to the direction of travel, so that the counterbalancing elfect will at times be less than under normal running conditions, and at other times greater. By this means, the rise can be increased, the car easily controlled, and power saved. In carrying out the invention, the car and plunger are balanced by another plunger connected therewith and means are provided for applying fluid pressure to the auxiliary plun er so as to at times tend to lift it, there y reducing its effective pull on the car, and at other times tend to retard it, thereby increasing its effective pull on the car. As shown herein the auxiliary cylinder is separate from the operating cylinder, but controlled simultaneously therewith, it being understood that the particular construction and arrangement of valves shown herein is simply illustrative of one means of applying the generic invention.

Specification of Letters Patent.

Patented Apr. 20, 1915.

Serial No. 355,358.

A further object of the invention is to pro vlde an elevator system wherein the car will be raised by the head of water in the aux- 1l1ary counterbalancing cylinder and lowered by its own weight in addition to the live load, when the counterbalancing effect of the auxiliary plunger is removed. In carrying out this object, the auxiliary counterbalancing cylinder containing the auxiliary plunger connected with the car, is disposed in part or wholly above the working cylinder, and connected with a pressure supply and with the main cylinder, While a valve is provided to open the main cylinder to the head of water in the auxiliary cylinder to raise the car and to admit pressure to the auxiliary cylinder while discharging from the main cylinder to lower the car.

In the accompanying drawings, Figure 1 represents in elevation, an elevator system embodying the invention; Fig. 2 shows a three-position valve mechanism for such an elevator system.

1 represents the car, carried by a plunger 3, which operates in the working cylinder 4. Attached to the car is the counterweight rope 5, running over sheaves 6, 7, moving sheave 9, and attached to the building at 10. The moving sheave 9 is mounted in a yoke 11, and attached thereto is a plunger or ram 13 which works in a cylinder 14 similar to the working cylinder 4, and a valve mechanism is provided to control the fluid pressure in both cylinders simultaneously. This arrangement of moving sheave counterweight, forms a two-to-one arrangement, in which the counterweight plunger 13 has the movement of the working plunger 8, thereby enabling the cylinder 14 to be disposed above ground in the elevator well, or adjacent thereto. It will be understood that another proportion of travel could be used if desired, as the advantage is that the expense of installation would be less with the cylinder above ground or only partially sunk therein. It will be obvious that the auxiliary plunger might be connected directly to the car, by sinking its cylinder in the same manner as the main cylinder.

The operation of the car by the main valve will take place in the ordinary manner, the speed being determined by the throw given the pilot valve by the operator. In the elevator systems in common use the mass of the counterweight is predetermined to be somewhat less than that of the car and plunger, and this difference remains constant in both directions and at various speeds. If however, it be desired to start the car up this can be accomplished much more quickly if it be nearly counterbalanced, and since the dead load to be lifted is closely counterbalanced, it becomes equally difiicult to stop, going up, because of the tendency of the plunger to bound ofi the water. Assuming the car to be approximately counterbalanced, it may, as can be seen, be easily started, and can be stopped quickly without bounding, if the pull, due to the mass and momentum of the counterweight or auxiliary plunger, be removed, so that the car during this period be uncounterbalanced temporarily to a great extent. By means of this invention, this result can be secured by a proportioning of the movements of the valve pistons, and their respective ports, such that the exhaust from cylinder 14 will be throttled to an extent suflicient to relieve the pull of the counterweight on the rope 5. Without this pull, the momentum of the now unbalanced car and plunger, going up is very quickly arrested by gravity, and a stop can be made as quickly as is permissible without discomfort to the passengers. To secure this result, it need not be necessary to throttle the auxiliary exhaust to such an extent as to cause the cables to slacken up, since the car becomes unbalanced as soon as the pull of the auxiliary plunger on the car is relieved.

In descending, where a car is approximately counterbalanced, it necessarily starts slowly, unless heavily loaded, but with this invention, by a proper proportioning of the valve pistons, sufficient pressure can be admitted to partially lift the auxiliary plunger, or move it faster in proportion to the car speed, thereby making the heavier car move more quickly. In stopping, going down, the stop can be made at any rate which will not buckle the plunger, in ordinary practice, but with this invention by throttling the supply to cylinder 1 1 as the valve closes, a pull is put on the auxiliary plunger side and thus the momentum of the moving mass decreased quickly without excessively compressing the plunger, or making it buckle under too great a strain. Also, where a car is closely counterbalanced, there is less compressing strain on the plunger, and less stress involved in starting and overcoming the inertia of the dead load.

In Figs. 1 and 2, a preferred development of the invention is shown in which the main cylinder has no direct connection with the pressure tank through the main valve,

' as is the ordinary practice. Instead of this,

the auxiliary cylinder is disposed above the ma n cylinder and the head of water in the auxiliary cyllnder used for lifting the car.

To lower the car the tank pressure is admitted to lift the auxiliary plunger and the main cylinder simultaneouslv opened to the exhaust thus permitting the car to move down at any rate desired. The pipes 20, 21, from the respective cylinders, are connected with a three-position valve 61, operated by a pilot valve in the manner before described. The valve 61 has a stem 62 carrying pistons 63, 6 1, G5, 66, 67, piston 64:, con trolling a connection between pipe 20 and the exhaust 68, while a simultaneous connection is made by pistons (35 and (36 between pipe 21 and the pressure supply tank. These connections will cause the auxiliary plunger to go up and thereby relieve the main plunger 3 of the weight, so that the car will start downward, and the water will discharge from the main cylinder as the plunger descends. To raise the car, the pressure supply will be cut off and the static pressure in cylinder 1 1 admitted directly to cylinder 41, by moving the valve stem 62 so that passages 20 and 21 are connected between pistons 65, 66. In this position, the supply pressure is cut off from the cylinder 14:, and the exhaust of cylinder 4 is closed by piston 65. lVhen the valve is in the center, both cylinders are cut off, as will be seen. Inasmuch as the auxiliary cylinder is entirely above the main cylinder, and the tank pres sure will exceed the static pressure of the column of water in the auxiliary cylinder, by opening the auxiliary cylinder to the tank, the auxiliary plunger will be raised, and the car lowered by its own weight. The speed of descent will be regulated by the amount of pressure admitted to the auxiliary cylinder, which can be regulated as desired in well known ways, as by proportioning the port area. To raise the car, it will only be necessary to apply suilicient pressure to overcome the live load and friction (the system being approximately balanced without live load), and this lifting pressure will be supplied by the head in cylinder 14-.

By making the displacement of plungers 3 and 13 equal, there will be no loss of pressure between the two cylinders. It will be seen that by throttling passages 20 or 21, that both cylinders will be affected and thus the speed readily controlled without straining the plunger. This may be accomplished by design of ports or in some other of the well known ways. Suitable automatic stop valves will also be provided for the ends, in pipes 20 and 21. Other forms of controlling valves may be used than this specific form. Inasmuch as the main plunger will only have to lift the live load, it can be made much lighter, and will therefore require less water and less operating power. Also it will, by reason of the approximate counterbalancing, be practicable to build this type of elevator for considerably higher rises than is practicable at the present time, without increasing the mass to be moved to such an extent as to require too great power. At the same time, such a system, will be capable of being easily controlled in starting and stopping. A still further advantage is in the safety of such a system, in case of separation of the plunger and car, for it will be seen that the counterweight cannot fall and jerk the car up to the top of the shaft. Also in case the water should escape from the auxiliary or main cylinder, the car would not rise suddenly, or fall.

It will be understood that the passages, ports, plunger areas, speed of valves, etc, will be proportioned according to the necessities of actual practice, and only a general statement of such details can be given herein, sufficient to explain the general results to be attained. Also it will be seen that the proportions of the auxiliary cylind-r and plunger, and the amount of additional weight it will carry, if any, will be determined by actual practice. In this connection, I wish it understood that by the term counten weight, I refer to the effective mass opposing the weight of the car and plunger, which, as herein described, will be made up of various elements other than the dead weight of the auxiliary plunger which may or may not be loaded in addition.

in referring to the valve 61 as a threeposition valve, I refer broadly to valves of the well-known three way type wherein there is a central closed position and opposite extreme open positions, one extreme open position causing the car to go up and the other causing the ear to go down, and the center closed position causing the car to remain stationary, such valves being usually controlled from the car by a controlling lever having corresponding positions. It will, however, be understood that the actuating connections for these three-position valves may be widely varied from that herein shown without departing from the invention.

The foregoing considerations have a direct and important bearing upon the problem of building high speed plunger elevators having rises of upward of two hundred feet, wherein, because of the large moving masses involved, the ability to positively and accurately control the movement becomes of paramount importance. With this inven tion, whereby the effective mass of the auxiliary plunger may be varied automatically, and the car more closely counterbalanced, without loss of control, many of the objections hitherto raised to this type of elevator can be obviated, and the elliciency increased.

It will of course be understood that the invention is not to be restricted to the particular means herein shown, as the invention may be embodied in other forms of apparatus without departing from its scope.

Having thus described my invention, I declare that what I claim as new and desire to secure by Letters Patent, is,

1. The combination with a main cylinder,

of a plunger therein, a car supported by said plunger, a second cylinder above said first cylinder, a counterweight plunger in said cylinder having equal displacement and one half the travel, relatively to said main plunger, a cable running over sheaves and connecting said plungers, a pressure supply, and valve mechanism for connecting said two cylinders to raise the main plunger and simultaneously lower the counterweight plunger in one open position, and in another open position connecting said counterweight cylinder to the supply and the main cylinder to the exhaust.

2. The combination with a hydraulic cylinder plunger and car, of an auxiliary cylinder located above said cylinder, a plunger in said auxiliary cylinder, a cable connecting said plunger and the car, and means whereby the static pressure of said auxiliary cylinder raises the car, and means for applying pressure to said auxiliary plunger and opening the main cylinder to enable the car to fall by gravity, substantially as described.

3. The combination with a hydraulic cylinder, a plunger and a car, of an auxiliary cylinder and plunger, means for raising the car by the static pressure of said auxiliary cylinder, and means for lowering the car upon admitting lifting pressure to said auxiliary cylinder, substantially as described.

4:. The combination with a hydraulic cylinder, a plunger therein, and a car carried by the plunger, of a second cylinder above said first cylinder, a counterbalance comprising a plunger moving therein and connected to said first plunger to have a less ratio of movement, and a controlling valve for simultaneously opening one of said cylinders to pressure and the other to exhaust to operate the car in one direction, and connecting the cylinders to operate the car in the other direction.

5. The combination with a hydraulic cylinder, plunger and car, of a counterbalance connected therewith, and having a lesser ratio of movement, a cylinder in which said counterbalance is adapted to operate, said cylinder being above the main cylinder, means for connecting said two cylinders to raise the car, and means for opening one cylinder to the exhaust and the other to a source of pressure to lower the car, substantially as described.

6. The combination witha main cylinder, of a plunger therein, a car supported by said plunger, a second cylinder above said first cylinder, a counterweight plunger in said cylinder having equal displacement and one half the travel, relatively to said main plunger, a cable running over sheaves and &

connecting said plungers, and a three position valve for simultaneously controlling the plungers in said respective cylinders, said valve at one position opening direct communication between said two cylinders.

7. In a hydraulic elevator, the combination of the car, a vertically acting plunger connected thereto, a cylinder for the plunger, a second vertically arranged cylinder, a plunger therein connected to the car by multiplying connections, and a controlling valve for the cylinders arranged when open so that said plungers will simultaneously move in opposite directions at different rates of speed, said valve at one open position connecting said two. cylinders, and at another open position connecting one to pressure and the other to exhaust.

8. The combination With a main cylinder, of a'plunger therein, a car supported by said plunger, a counterweight cylinder above said main cylinder, a counterweight plunger in said cylinder having equal displacement and one-half the travel, relatively to said main plunger, a cable runningover sheaves and connecting said plungers, a pressure supply, and a three-position valve mechanism for simultaneously connecting either of said cylinders to exhaust Water therefrom and the other to pressure to operate the car in both directions, said valve mechanism and its connections being constructed and arranged, in one position thereof, to cause circulation directly between the two cylinders for the purpose set forth.

9. In a hydraulic plunger elevator, the combination with a cylinder, a plunger, and a car carried thereby, of counterbalancing means connected with the car and comprising a second plunger, a motor for lifting the counterweight by means of said second plunger, and a three-position valve for simultaneously connecting either motor to a source of power and the other to exhaust water therefrom to operate the car in both directions, said valve mechanism and its connections being constructed and arranged, in one position thereof, to cause circulation directly between the two cylinders for the purpose set forth.

10. The combination of an elevator, a counterbalancing plunger arranged in a cylinder and connected to the car, a valve mechanism for controlling the flow of liquid to and from the counter-balancing cylinder arranged so that as the car is stopped on its upward movement the flow from the counterbalancing cylinder will be stopped automatically, a cylinder and plunger independent of the counter-weight for operating the car, and means for connecting said cylinders.

11. In an elevator system, the combination with a main hydraulic plunger carrying a car, of a counterweight and plunger opposing the weight of the car and connected thereto by ropes, means for applying power from the counterweight cylinder to the main plunger to lift the car while the supply pressure is cut off, and for applying power to the counterweight plunger and opening the main cylinder to exhaust to lower the car, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

JOHN SHERMAN HOYT. Vitnesses JULIAN S. Voosrnn, GEO. A. HOFFMAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. C. 

